2026 ICD-10-CM Diagnosis Code D55.9Anemia due to enzyme disorder, unspecified

ICD-10-CM Codes›D50–D89›D55-D59›D55

ICD-10-CM D55.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D55.9 is a billable ICD-10-CM diagnosis code for anemia due to enzyme disorder, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 811 through 812. Coders also document this condition as anemia due to enzyme deficiency. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hemolytic anemia.

Code Identity

ICD-10-CM Code
D55.9
Billable Status
Yes — Valid for Submission
Code Describes
Anemia due to enzyme disorder, unspecified
Short Description
Anemia due to enzyme disorder, unspecified
Same as the full description in the CMS dataset.
Parent Code
D55
Anemia due to enzyme disorders

Code Classification

ChapterD50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
SectionD55-D59Hemolytic anemias
CategoryD55Anemia due to enzyme disorders
This CodeD55.9Anemia due to enzyme disorder, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anemia due to enzyme deficiency
  • Anemia due to enzymopathy
  • Chronic non-spherocytic hemolytic anemia

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • deficiency
        • enzyme
    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • due to (in) (with)
        • enzyme disorder
    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • hemolytic
        • due to
          • enzyme disorder
    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • hemolytic
        • hereditary
          • due to enzyme disorder

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR BLD002
Hemolytic anemia
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Anemia due to Enzyme Disorder

    any form of anemia that results from the absence of, or the defective action of, any enzyme.

Patient EducationClinical

Anemia

If you have anemia, your blood does not carry enough oxygen to the rest of your body. The most common cause of anemia is not having enough iron. Your body needs iron to make hemoglobin. Hemoglobin is an iron-rich protein that gives the red color to blood. It carries oxygen from the lungs to the rest of the body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert D55.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
282.3 Enzyme defic anemia NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D55.9Overview

Is D55.9 (Anemia due to enzyme disorders) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report anemia due to enzyme disorder, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D55.9 group to?

When anemia due to enzyme disorder, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 811, 812, with relative weights from 0.9182 to 1.4043 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D55.9?

Under the General Equivalence Mappings, anemia due to enzyme disorder, unspecified converts to ICD-9-CM 282.3 (enzyme defic anemia NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.